Optical amplifiers are employed in the field of optical transmission technology for amplifying the optical signals transmitted in an optical network. Said optical signals in many cases run over long links measuring several hundred kilometers and more in an optical fiber, being attenuated in the process. It is therefore necessary to amplify the optical signals when they have been transmitted over long links.
FIG. 1 is a schematic diagram of a typical optical transmission link, or a part of a transmission network, having a transmitter 1 (TX), a receiver 9 (RX), and two amplifiers 3. An optical signal emitted by the transmitter 1 therein runs over a plurality of sections of an optical fiber 2 to the receiver 9 and is in each case after a predefined link amplified or refreshed by an amplifier 3.